South Africa’s wave of violence against foreigners is vile and depressing.

Not so much because ‘black’ South Africans should love and respect foreigners from elsewhere in Africa. Why should they?

But the fact that South Africa’s uniquely horrible live burnings are back.

Remember necklacing? The practice of placing a petrol-filled tyre over a fellow Africa’s shoulders then setting it alight? Winnie Mandela (in)famously endorsed this technique of revolutionary terror.

The then ANC leader Oliver Tambo used curiously mild language:

"Of course we are not in favor of necklacing. We don’t like necklacing, but we understand its origins. It originated from the extremes to which people were provoked by the unspeakable brutalities of the apartheid system."

So what is ‘provoking’ this latest round of mayhem? What are its ‘origins’?

The ANC leadership’s busy unspeakable attempts to steer into the long grass international condemnation of the Mugabe regime, whose unspeakable brutality has driven hundreds of thousands of Zimbabweans to cross into South Africa?

Or is it demographic trends, accelerated by ANC policies?

For a long time Africans have been making their way to South Africa to try to make a living. Down in Cape Town in 1988 my Polish friends in the city council told me how they grappling with finding interpreters to speak languages from as far away as Kenya – people had walked or hitch-hiked thousands of miles from there to tin shacks on the beach near Cape Town.

But the suicidal Mugabe regime has caused a far larger exodus, across South Africa’s own borders. Not too surprising that poor South Africans are fed up, even if the scale and intensity of the violence is appalling.

I recall a senior diplomat telling me that South Africa was not really different from other disasters in Africa. It eventually would crash into the ground, but thanks to its higher living standards it would descend from a far higher altitude and with a shallower trajectory.

Sure seems to be going that way.